Custom Model Binder - How to revalidate

Question

Hi there,

I'm using ASP.NET MVC 2 and want to figure out how to re-trigger the validation on my model after it has been populated using a custom binder.

So, I start with a couple of EF classes which are associated, Booking and Traveller (each booking can have one or more travellers)

Here's the buddy class I'm using to place balidation on Booking:

[MetadataType(typeof(Booking_Validation))]
public partial class Booking {
    // partial class compiled with code produced by VS designer
}

[Bind(Include="Name")]
public class Booking_Validation {

    [Required(ErrorMessage="Booking name required")]
    public string Name { get; set; }

    [AtLeastOneTraveller(ErrorMessage="Please enter at least one traveller")]
    public EntityCollection<Traveller> Travellers;

}

public class AtLeastOneTraveller : ValidationAttribute {        
    public override bool IsValid(object value) {
        if (value != null) 
            return ((EntityCollection<Traveller>)value).Count > 0;
        return true;            
    }
}

I use a custom model binder to populate the booking and it's associated travellers, except that ModelState.IsValid seems to be set even before my custom model binder has had a chance to add the travellers to the booking object, even even after doing so, ModelState["Travellers"] still contains the validation error saying there must be at least one traveller attached.

Is there any way to re-trigger validation after the custom model binder has done its thing?

Answer 1

Have you tried the TryValidateModel method on the Controller class?

http://msdn.microsoft.com/en-us/library/system.web.mvc.controller.tryvalidatemodel.aspx

Answer 2

try this: http://shazwazza.com/post/Custom-MVC-ModelBinder-with-Complex-ModelsObjects-using-built-in-MVC-Validation.aspx